For as long as I can remember, I've been having issues with scrolling in Windows and its applications. When scrolling via dragging the scroll blob, it seemed as if Windows had the annoying habit of randomly resetting your scroll blob to its starting position, which irritated me to no end. It took me a while to figure out, but I finally know when this behaviour occurs - now I just need to know: why?!

Did you try the middle mouse button? Works for me™
Like someone else said shift+click also jumps to where you point it to (tested with firefox).

With many programs I have scroll up/down grouped (firefox does have it like that) on the bottom and also a scroll button at the top but this seems to depend on the program, some do not have the scroll up/down grouping (skype 2.0.0.72 for example). Maybe this depends on the theme in use.